The past several decades have been marked by tremendous growth in the types of window covering materials that are available to purchasers. Starting with roller shades and slatted horizontal blinds, the field of window coverings has blossomed to include a wide array of different types of coverings. These have included pleated shades, Roman shades, cellular shades, and many others.
Among these many choices, there are shade materials which are transparent to some degree, as well as shade materials which are much more opaque, keeping out a much greater degree of light and providing a greater degree of privacy than is offered by shade materials that are substantially transparent.
In recent years, the window covering industry has seen the advent and increased popularity of double shades. As illustrated, for example, in U.S. Pat. No. 5,205,334 in the name of Ren Judkins, double shades provide an opportunity to employ two completely different types of shades mounted together to cover the same window. With such double shades, the user has the ability to deploy only the first of the two shades (which may, for example, be a relatively sheer pleated shade), or to only deploy the second shade, which may be a more opaque roller shade, or to deploy both at the same time. Double shades are often purchased and manufactured on a custom basis, with the customer not only selecting the two shade fabrics, but also dimensions calculated to accurately cover the customer's window.
All of these choices present manufacturers with various challenges. Whatever type of shade the customer may choose, and whatever size may be needed by the customer, the manufacturer must be able to provide the double shade with those selections in a completed shade that includes a headrail and the appropriate controls for raising and lowering each of the two shades.
Double shades should preferably be as compact as possible. Systems which simply join two shades together are likely to be bulky and awkward, are likely to have a headrail that is as large as (or even larger than) two separate headrails that are simply tied together, thus wasting space and material, and may even need to be mounted independently. In addition, double shades should avoid, to the extent possible, light gaps which allow light to enter a room around the edges of the shades.
Moreover, a system is needed whereby double shades can be custom built to the customer's requirements in an economic fashion by fabricators and others who wish to minimize the costs associated with maintaining inventories of various components. With particular regard, for example, to headrails used with double shades, the width of the headrail will be a function of the width of the individual customer's window. If one wished to maintain stock sizes, a substantial number of sizes would have to be inventoried. Even if one were willing to maintain a smaller number of stock sizes of headrails and trim them to size, there would inevitably be a degree of waste of material. It would be more economical to be able to maintain long lengths of headrail that can be cut individually to the exact size needed with a minimum amount of waste.
It is also desirable that the headrail per se not have any finished openings, such as an opening to receive lift or control cords. Since such finished openings must be smooth and attractive, they will typically have to be made at a factory.
The hardware needed for raising and lowering the shades and holding them in a desired position presents similar challenges in the environment of double shades. Certain types of shades are best used with lift cords which include cord locks, such as pleated shades, while certain other types of shades are most effectively used with clutch mechanisms, such as roller shades. It would be particularly beneficial for fabricators and other manufacturers to be able to select the two mechanisms that are most appropriate for the two shades that are going to be employed on a particular double shade.
Thus, a need has arisen for a system for manufacturing double shades that provides a simple and compact construction, minimization of light gaps, flexibility to manufacturers in terms of width of the shade, the fabrics used on the shade, and the hardware for operating the shades, and which also minimizes labor, tooling and the need for extensive inventory of numerous components.